This application claims the benefit under 35 U.S.C. Section 119 of Japanese Patent Application Serial No. 2001-248365, filed Jul. 16, 2001, which is hereby incorporated by reference in its entirety into this application.
1. Field of the Invention
The invention relates to an ophthalmic surgical contact lens which is used especially in cataract and intra-ocular lens (IOL) implant surgeries.
2. Description of the Related Art
Cataract and IOL implant surgeries are effective in the treatment of cataract and are used for refractive correction in ophthalmology. Such surgeries are performed under a surgical microscope.
More particularly, a coaxial illumination of the surgical microscope is focused on the ocular fundus of a patient""s eye to improve a surgeon""s visibility. It has been found that such microscopic light during surgery, however, can be harmful, causing what is known as operation microscope retinopathy (e.g., erythropia) or retinal photo-toxicity. For example, the Japanese magazine xe2x80x9cOphthalmology MOOKxe2x80x9d No. 47, 1992, pages 131-145, reports that the occurrence of such retinopathy is as high as 35%, and the U.S. magazine xe2x80x9cAmerican Journal of Ophthalmologyxe2x80x9d, vol. 103, 1987, pages 255-263, reports 7.4%. Thus, these magazines conclude that such retinopathy is of significant concern.
The following methods have been used in an attempt to prevent this retinopathy, and visual acuity reduction in patients: oblique illumination, a light-filter or a light-shield on the cornea. Usually, the light-shield is chosen from a sponge, a light-shield lid or a black contact lens.
Further, a patient""s cornea is exposed to air during cataract and IOL-implant surgeries. That is, the patient""s eyelids are kept open with a speculum during the surgery, so the patient cannot blink. The surgeon must keep the patient""s eye wet during the surgery.
Generally, continuous circular capsulotomy is performed in cataract surgery. It is a very delicate operation, and occasionally the surgeon may tear an equator of the lens capsule, or scratch the cornea. The disruption of the lens capsule or distorted capsulotomy may lead to mispositioning of an IOL that is subsequently implanted in the capsule.
There are many diagnostic and surgical lenses for ophthalmic uses. Surgical lenses are used mainly for iridectomy, trabeculectomy, vitrectomy, retinal detachment surgery, goniotomy, expulsive choroidal hemorrhage surgery, etc. The diagnostic uses are for observing the gonio angle, iris, vitreous cavity, ocular fundus, etc. The optical shapes of these ophthalmic surgical lenses are typically plano-concave, bi-concave, convex-concave (meniscus) and prism-concave.
U.S. Pat. No. 5,021,057 discloses a relatively hard lens intended to help stop the effusion of ocular material in the event of expulsive choroidal hemorrhage during anterior segment surgery. The lens is placed over the incision to block flow from the eye. The patent also discloses a radial slot in the lens that allows suturing to close an incision while pressure is applied to the eye globe. The device must be rotated to create more than one suture.
It is a purpose of the present invention to prevent corneal disorder in a patient by avoiding corneal scratches caused by surgical instruments, prevent corneal physiological malfunction caused by air, and provide a continuous presence of ophthalmic solution during ophthalmic surgery.
It is another purpose to provide an ophthalmic surgical lens that leads to more successful cataract surgery and/or IOL implant surgery.
It is still another purpose to provide a lens that reduces a patient""s corneal refractive power during surgery, while dispersing microscopic illumination on a patient""s ocular fundus.
It is another purpose to provide an ophthalmic surgical lens to be placed on a patient""s cornea, which lens is effective in preventing operation microscope light retinopathy, and avoiding damage to the cornea due to incisions being made during surgery.
It is also a purpose to provide a surgical lens that can be used during the entire surgical procedure.
It is another purpose of the present invention to provide a surgical lens which facilitates the immediate removal of a luxated cataractous lens or an IOL, both captured in the vitreous cavity, during cataract or IOL implant surgery.
To achieve the foregoing and other purposes of the present invention there is provided a surgical lens, including a lens portion having a concave surface that simulates a human corneal surface, at least one haptic that extends from or supports the lens, and at least one aperture adjacent the haptic. The at least one aperture exposes the ocular surface so that an incision can be made therein, but the lens portion protects the cornea. Several apertures may be needed in the area within the over-all length of the lens, depending on the types of surgery.
The lens is preferably made of a soft material selected from silicones, acrylic resins and plastics. The periphery of the lens surface or the haptic surface is preferably a circle for use in regular ophthalmic surgeries.
A small amount of viscous ophthalmic solution, such as sodium hyaluronate solution, condroitin sulfate solution or methyl cellulose solution, is applied on the surface which is placed on the patient""s cornea. The corneal surface is thus separated from the air by the ophthalmic solution.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.